On track-type work machines such as belted agricultural tractors, it has long been desired when pulling certain heavy tillage work implements, such as chisel plows and field cultivators, to turn or pivot these towed implements about a point at or in front of the pivot center of the tractor. On the other hand, it has also been a desire to pivot other work implements, such as row crop equipment, about a point approximately two feet behind the centerline of the track driver of the tractor.
The prior art in wheeled tractors is replete with variations of drawbar-related devices for hitch articulation and manipulation, but such art does not necessarily transfer to track-type machines. For example, one characteristic of track-type machines not found in wheeled machines is the tendency to push a towed work implement to an opposing side as the track-type machine turns. This characteristic is often undesirable on agricultural work machines, especially in the row crop applications where accurate locating of the towed implement is important. On the other hand, having an implement pivot point near the work machine pivot point is desirable where high pulling forces are required. What has been desired then, is a hitch particularly for a track-type machine, with a variable pivot point.
The present invention is directed to overcoming one or more of the problems set forth above.